The present invention relates generally to brewable beverage making machines, which can use tea, coffee, cocoa, hops, malts and grains for such brewing.
A single serve coffee brewing machine sold under the registered trademark KEURIG has become very popular. This machine uses a single portion cartridge or packet sold under the registered trademark K-CUP. Each packet includes a cup packed with a brewing material, such as coffee, and sealed air tight at its upper open end with a foil lid. A similar machine is sold under the trademark NESPRESSO.
When the packet is placed in one of its brewing machines, the brewer punctures the foil lid with a spray nozzle and the bottom wall of the packet with a discharge nozzle. Coffee grounds are held in the packet. Hot water under pressure is supplied through the spray nozzle, mixes with the coffee grounds, and then exits through the discharge nozzle to a coffee mug positioned by the user below the discharge nozzle.
With this arrangement, however, the output punched hole is basically the same size as the input punched hole, so that there is no steeping or residence time of the hot water in the packet, that is, the water quickly flows through the coffee and out the punched outlet hole. Further, as the water enters the packet, air in the packet rises as a bubble of air. However, because the only inlet opening is the punched hole in the foil lid through which the water is supplied, there is nowhere for the air to escape. As a result, the pocket of air further prevents the water from rising in the packet to properly mix with all of the coffee grounds, as well as providing added pressure for pushing the water quickly out of the punched outlet hole.
In addition to being used with coffee, the packets sold under the trademark K-CUP also include tea leaves for brewing tea, cocoa for making hot cocoa beverages, as well as fruit brews for making fruit drinks.
The KEURIG system also includes a refillable cartridge or basket with a filter that can be inserted therein and filled with a brewable material sold under the trademark MY K-CUP. A top is provided with an opening that is always open and receives the input nozzle of the machine, as well as having side air vents for fluidly connecting the interior with atmospheric pressure. The bottom of the basket includes at least one outlet discharge opening, which has a greater area than the inlet water opening in the top. Thus, there is no need for any puncturing devices. To fit this device in the Keurig machine, a sub-housing must be removed first.
However, with the refillable basket, because the outlet opening has a greater area than the inlet opening, and because of the vent openings, the hot water input into the basket will flow very rapidly out through the outlet discharge opening, with very little steeping or residence time.
With the above systems, the hot water does not always sufficiently extract the flavor from the material in the packet. This is because the water flows into and out of the cartridge very quickly, without providing sufficient time to extract the flavor from the materials in the cartridge. This is particularly the case with tea leaves, where it is necessary for the hot water to interact with the tea leaves over a larger time period.
The same applies to conventional coffee and tea brewing machines.